Coordinating control linkage



March 21, 1967 n. N. MEYERS ETAL 3,3@99933' COORDINATING CONTROL LINKAGE Filed Feb. z, 1965 2 sheds-sheet n.

BY Wascrw March 21, 1957 D. N. MEYERs ETAL,

COORDINATING CONTROL LINKAGE Pwi? Filed Feb. 2, 1965 2 Sheets-Sheet 2 LEG TQGU K@ BY W ctSx/Ll'wuwgn am mai ATTORNEYS United States Patent O 3,309,937 COORDINATING CONTROL LINKAGE Donald N. Meyers, Philadelphia, Pa., and Oleg Stroukoff,

Gloucester City, NJ., assignors to Piasecki Aircraft Corporation, Philadelphia, Pa., a corporation of Pennsylvania Filed Feb. 2, 1965, Ser. No. 429,814 8 Claims. (Cl. 74-471) This invention relates to apparatus for coordinating control of two mechanisms which combine to produce desired effects, but which are controlled in one predetermined relation under one set of operating conditions, and in another predetermined relationship under another set of operating conditions. More particularly, the invention relates to such apparatus particularly adapted to coordinate control of propeller pitch and vane deflection in the ring tail of a compound helicopter such as is disclosed in Patent No. 3,138,349 and my copending application Ser. No. 357,197, filed Apr. 3, 1964 now Patent No. 3,241,791, and is an improvement over the control means disclosed in Patent No. 3,138,349.

The control apparatus disclosed in Patent No. 3,138,- 349 operates upon the concept that for hovering and low speed forward flight, the vanes in the ring tail would be set at a fixed deected position, and yaw control would be entirely through change in propeller pitch. For cruising ight, however, propeller pitch is separated from rudder control and the vanes are set at approximately neutral position and controlled about this position in the -manner of conventional rudders.

It is desirable that the rudder vanes be connected at all times to the rudder pedals, but the rudder vanes must -be deflected at different degrees under dillering conditions to obtain the same amount of yaw control. For example, the rudder surfaces must be of sucient size to produce a strong side force to counteract rotor torque in hovering, with only the propeller slipstream to develop this force. In high speed cruise, on the other hand, these large rudders, if permitted their full amount of deflection, would develop a destructively large side force, and must be limited to quite small deiiections. It the rudder vanes are to be connected to the rudder pedals at all times, it is necessary that the vanes be deected different amounts for similar pedal movement under diilerent iiight conditions.

The principal object of the present invention is to provide coordinating control linkage which will provide a varying ratio of rudder pedal to rudder vane movement under conditions of hovering and cruising flight.

As, ideally, this varying ratio should be controlled by airspeed, and propeller pitch in steady ight is a function of airspeed (since the propeller r.p.m. is approximately constant) it is a further object of the invention to provide coordinating linkage of the type described wherein the position of the usual propeller pitch control lever dictates the rudder pedal to vrudder vane ratio.

Another object is the provision of such linkage which controls both rudder vanes and propeller pitch when in hovering regime, so that left rudder (to counteract rotor torque when rotor rotation is counterclockwise when viewed from above) results in `an increase in propeller pitch.

Other objects of the invention will become apparent from the following description of one practical embodiment thereof, when taken in conjunction with the drawings which accompany, and form part of, this specification. In the drawings:

FIGURE 1 is a top plan View of control apparatus embodying the principles of the present invention;

FIGURE 2 is a side elevation of the apparatus shown 3,309,937 Patented Mar. 2l, 1967 in the position `for minimum propeller pitch and maximum rudder defiection ratio;

FIGURE 3 is a View similar to FIGURE 2, with the apparatus adjusted for maximum propeller pitch and minimum rudder deection ratio;

FIGURE 4 is a vertical section taken on the line 4 4 of FIGURE 2;

FIGURE 5 is a vertical section taken on the line 5 5 of FIGURE 2; and

FIGURE 6 is a vertical section taken on the line 6-6 of FIGURE 2.

In general, the coordinating control linkage of the present invention serves to determine the amount of movement imparted by a pedal-operated quadrant through the linkage to a rudder vane-operating quadrant, to provide more or less vane movement in response to pedal operation in accordance with the ight regime for which the pitch of a shrouded tail propeller is set. Under certain circumstances, and in certain set conditions, vane movement is accompanied by pitch variation.

Referring to the drawings in detail, there is shown a quadrant 1 which is rocked by cables 2, connected to conventional rudder pedals (not shown). Rocking movement of quadrant 1 is transmitted through linkage, indicated generally as 3, to a quadrant 4, connected by cables 5 to rudder vanes (not shown) which maybe of the type shown in Patent No. 3,138,349, or in my copending application of Ser. No. 357,197, led Apr. 3, 1964. The two quadrants are mounted on xed centers adjacent opposite ends of a linkage mounting plate, or frame, 6. Quadrant 1 is mounted on plate 6 by pivot pin 7, and quadrant 4 is rotatably mounted by pivot pin 8. The quadrants are conventional in form, having opposed arcuate edges which are grooved to receive the respective operating cables 2 and 5.

Quadrant 1 is coupled to quadrant 4 by a connector 9 composed of a number of elements. These include a link 10 pivoted at 11 at one end to quadrant 1, and at its Opposite end by a pivot 12 to one end of a tie rod 13. The other end of tie rod 13 is pivoted to an arm 14 of a lever 15, swingably mounted at 16 on the plate 6. A second arm 17 of lever 15 is connected to a second tie rod 18 coupled to a valve control 19 of a hydraulic actuator 20. The actuator forms part of the connector 9 in those installations where rudder loads are too high for direct operation, lbut will not be required where rudder loads are light. Actuator 20 has its piston rod 21 connected by pin 22 to plate 6. An arm 23, at the opposite end of the actuator, is Connected vby pivot 24 to a crank arm 25 of the quadrant 4. Thus, movement of quadrant 1 will cause inter-connected members 10, 13, 14 and 15 to move the value control 19 of the actuator 20 and the actuator, in turn, will transmit movement to the quadrant 4 in direct rati-o to the movement given the value control.

Actuator 20 is of conventional type, and can be electric, pneumatic or hydraulic, although the one shown is hydraulic wherein movement of the valve control 19 couples a cylinder to a source of fluid under pressure to either extend `or retract a piston. By having the piston rod anchored, the casing moves until it closes' off the valve. By this means, the actuator is caused to move an equal distance to movement given the valve control, in the direction of movement given the valve control.v

It is evident, that the amount of movement transmitted by linkage 9 to the quadrant4 depends upon the distance travelled by pivot 12 when quadrant 1 is rocked. The distance travelled by pivot'12 for any given degree of rocking of quadrant 1 is governed by the distance pivot 12 is held from the pivot axis of quadrant 1. The greater the distance from pivot 7 to pivot 12, the greater will be the distance travelled by pivot 12. In order to control the rudder deection is required to oiset rotor torque.

position of pivot 12 relative to pivot 7, pivot 12 not only connects arm to tie rod 13, but to one end of a link 26 as well. The other end of link 26 is attached to arm 27 of a bell-crank 28 pivotally mounted on the plate 6 at 29. Arm 30 of the bell-crank is connected to a control bar 31 which has its opposite end connected pivotally to the top of a propeller pitch control lever 32. Lever 32 is pivoted at its other end to arm 33 of bell-crank 34, pivotally mounted at 35, on quadrant 4. Intermediate the ends of lever 32 there is a connection to a movable rod 36 of an actuator 37 pivotally connected at 38 to the plate 6. The actuator is operated from a propeller pitch control (not shown) in the pilots compartment. Movement of the actuator will cause lever 32 to pivot about its connection 39 with arm 33 of bell-crank 34. This will cause movement of control bar 31 to rock bell-crank 28, and, through movement of link 26, shift the location of pivot 12 toward or from pivot 7 of quadrant 1. Lever 32 is also connected to a rod 49 at 41, which is coupled to, and operates, the propeller pitch changing mechanism (not shown). Thus, actuator 37 serves to adjust the propeller pitch and to change the setting of the pivot 12.

The bell-crank 34 has a second arm 42 which is tethered to the mounting plate 6 by means of an anchor link 43, connected to the arm 42, at 44, and to the mounting plate, at 45. With this arrangement, the bell-crank 34 Will be caused to rock about its pivot on quadrant 4 every time the quadrant is moved. An examination of FIGURE 2 which shows quadrant 4 in a neutral rudder position, will show that when quadrant 4 is rocked through small angles in either direction, the movement of the connection 39 between arm 33 of the bell-crank and the lever 32 will have a major vertical component and negligible horizontal movement. This will result in vertical movement of lever 32, and will not cause appreciable longitudinal movement of either the pitch control rod 40 or the control bar 31. Thus, during small deflections from a neutral rudder position there will be no change in propeller pitch, nor any change in the setting of pivot 12. Therefore, the rudder pedal ratio will remain unchanged during this degree of rudder movement. This is the normal operation while the craft is in high speed forward flight. During this operation, the propeller is set at high pitch, and this, through control bar 31, has caused the pivot .12 to be adjusted to its closest position to the center of quadrant 1. With this adjustment, full rudder pedal movement will cause but small angle detiection of the rudders.

For hovering, or slow forward speeds, much greater This is normally a left rudder control for counterclockwise rotor rotation, and the propeller will be adjusted to much less pitch. To accomplish this, the pilot will operate his pitch control to energize actuator 37 through wires 46 to retract the actuator rod 36 to swing the control lever 32 about its connection 39 with arm 33 of bell-crank 34. This will result in clockwise movement of lever 32 (as viewed in FIGURE 2) and cause both control rod 40' and control bar 31 to move to the right. Movement of the control rod 40 will decrease the propeller pitch, and movement of control bar 31 will rock bell-crank 28 and, through link 27, shift the pivot 12 further from the center of rotation of quadrant 1. This results in the transmission of increased movement of quadrant 4 for any given increment of movement of quadrant 1. Consequently, movement of the rudder pedal will cause much greater deflection of the rudders.

The greater the arc of movement of quadrant 4 from its neutral rudder position, the further bell-crank 34 will be rocked about its pivot. As the arc of movement of the quadrant increases, the movement of the pivot 39, between the lever 32 and bell-crank arm 33, will include less vertical component and more horizontal component. Horizontal movement of pivot 39 will cause control lever 32 to swing about its connection 47 with the pitch actua- 4 tor rod 36. The direction of horizontal movement of pivot 39 is to the right (as viewed in FIGURE 2) which causes counter-clockwise movement of lever 32, and consequent movement of pitch control rod 41 to increase propeller pitch, and control bar 31 which will provide some further adjustment of the pivot 12. Thus, as the deflection of the rudder increases to counteract rotor torque, the propeller pitch is also increased to provide greater thrust against the rudder. The increase in both rudder deflection and propeller pitch results in more positive control with less rudder movement. This is the setting shown in FIGURE 3.

It may be desirable in some instances to provide a link connection between the control lever 32 and some fixed portion of the aircraft to hold the outer end of lever 32 to movement in a single plane without sidesway. This can be accomplished by connection of a pair of pivotally connected links 4S and 49 to the lever 32 at its top and to a xed portion 50 of the aircraft.

While in the above, one practical embodiment of the invention has been shown and described, it will be understood that the specific details of construction dislosed are merely for purposes of illustration, and the invention may take other forms within the scope of the appended claims.

What is claimed is:

1. Control linkage for coordinating movement of two output instrumentalities each having variable movement comprising, a mounting frame, a driving element pivot- -ally mounted on the mounting frame, a driven element pivotally mounted on the mounting frame, means coupling the driving and driven elements to transmit movement from the driving to the driven elements, means on the driven element for connection to one of said output instrumentalities whereby the said one instrumentality will be moved when the driven element is moved, and means to adjust the means coupling the driving and driven elements to vary the ratio of driving element movement transmitted to the driven element including means for interconnecting the means coupling the driving and driven elements and the second of said output instrumentalities and responsive to position settings of the said second output instrumentality.

2. In control linkage as claimed in claim 1 wherein, there are means for adjusting the position setting of the said second output instrumentality.

3. In control linkage as claimed in claim 1 wherein, there are means interposed between the driven element and the means to adjust the means coupling the driving and 4driven elements operative during maximum movement range of the driven element to automatically change the position setting of the said second output instrumentality.

4. In control linkage as claimed in claim 3 wherein, there are manually initiated means for adjusting the position setting of the said second output instrumentality.

5. Control linkage for coordinating movement of two output instrumentalities each having variable movement comprising, a mounting frame, a driving quadrant pivotally mounted in the mounting frame, a driven quadrant pivotally mounted on the mounting frame, means on the driven quadrant for connection to one of said output instrumentalities whereby the said one output instrumentality will be moved when the driven quadrant is moved, link means connected to the driving quadrant and the driven quadrant to transmit motion of the driving quadrant to the driven quadrant, the connection between the link means and the driving quadrant being shiftable toward and from the pivotal mounting of the driving quadrant, and means for interconnecting the second of said output instrumentalities and said link means to shift the position of said connection in response to change in the position setting of said second output instrumentality, whereby the movement transmitted from the driving quadrant to the driven quadrant will vary with the position setting of the second of said output instrumentalities.

6. In control linkage as claimed in claim 5 wherein, there is a lever included in said means for interconnecting the second of said output instrumentalities and said link means, and a manually controlled -actuator connected to the lever, whereby the position setting of the said second output instrumentality may be controlled.

7. In control linkage as claimed in claim 6 wherein, the lever in said means for interconnecting the second of said output instrumentalities and said link means is connected therein at one end of the lever, and the `opposite end of the lever is connected to a rst arm of a bell-crank pivotally mounted on the vdriven quadrant -and having `a second arm tethered to the mounting plate, the position of said bell-crank and lever being such that during small movement of the driven quadrant from a neutral position the lever will be held against movement to adjust the setting position of said second output instrumentality.

8. In control linkage as claimed in claim 5 wherein, said link means includes a two part link and comprises a power actuator, one part of the two part link operatively connecting the driving quadrant and the actuator to actuate the actuator upon movement of the driving quadrant and the other link part being the Aactuator connected to the driven quadrant to transmit movement from the actuator to the driven quadrant.

References Cited by the Examiner UNITED STATES PATENTS MILTGN KAUFMA, Primary Examiner. 

1. CONTROL LINKAGE FOR COORDINATING MOVEMENT OF TWO OUTPUT INSTRUMENTALITIES EACH HAVING VARIABLE MOVEMENT COMPRISING, A MOUNTING FRAME, A DRIVING ELEMENT PIVOTALLY MOUNTED ON THE MOUNTING FRAME, A DRIVEN ELEMENT PIVOTALLY MOUNTED ON THE MOUNTING FRAME, MEANS COUPLING THE DRIVING AND DRIVEN ELEMENTS TO TRANSMIT MOVEMENT FROM THE DRIVING TO THE DRIVEN ELEMENTS, MEANS ON THE DRIVEN ELEMENT FOR CONNECTION TO ONE OF SAID OUTPUT INSTRUMENTALITIES WHEREBY THE SAID ONE INSTRUMENTALITY WILL BE MOVED WHEN THE DRIVEN ELEMENT IS MOVED, AND MEANS TO ADJUST THE MEANS COUPLING THE DRIVING AND DRIVEN ELEMENTS TO VARY THE RATIO OF DRIVING ELEMENT MOVEMENT TRANSMITTED TO THE DRIVEN ELEMENT INCLUDING MEANS FOR IN- 